Irwin had 81 percent of the vote at 12:30 a.m., while his Republican challenger John Spisak received 18.11 percent.

In a victory speech to a crowd of about 100 Democratic supporters at the Washtenaw County Democrats watch party at the Weber Inn in Ann Arbor, Irwin said he looks forward to fighting for social issues in the state.

"I'm really excited to go back up there and keep fighting for education funding, protecting clean air and clean water, and fighting for equal rights for all of our citizens no matter who they love,” Irwin said. “We have a lot of work here to do here in Lansing and a lot of work to do here in Michigan."

This is a developing story. Check back at michignadaily.com for more updates.